Fbank joseph cbttpi



' is as follows 16 ounces of cellulose nitrate (11 I grains from thebacking 40 'amlples'of which may bestated as follows:

. of gum resins (25% copal --25 vide a coating,

solvents and such characteristics necessary for handling and which theabrasivegrains Reissuedlqova19, 929

. UNITED STATES:

; Re. 11,49i

PATEN T [OFFICE FRANK JOSEPH CRUPI, OF BROOKLYN,

' EOBATION, A GORPORA'IIONiOF NEW YORK warr nrnoor ABRASIVE manic mrmwmOriginal No. 1,642,766, dated September-20,1927, Serial No. 693,903,flied February 19,1924.

.Applicfition for reissue filed October This invention relates to andhas for its object the production of a waterproof sandpaper or'abrasivcfabric capable of withstanding disintegration when used on wet surfaces.

According to the present invention I pro trate, cellulose acetate,'orthe like) as distinguished from oils, varnishes, or resins. Thecellulosic material is soluble in a variety of easily vaporizablesolvents or mixtures of a solution possesses the application. L I Theprinciples of this invention may be applied in connection with a largevariety of formulae. The relative amounts'of cellulose nitrate,

obviousl desired or every particular operation. One formula suitable foruse in the production of the sand-paper of this invention, especiallyappropriate'with relation to admixture with other material to behereinafter referred to,

The cellulosic .material of the foregoing solution is the basis of thecoating of the present Y invention and supplies the means by areretained on the base paper or backing material with sufiicient tenacityto resist separation of the abrasive is used in association w th water;In connection with'the cellulosic solution I prefer to use one or moresupplemental solutions, ex-

5 sandarac), II. 4 pints of denatured alcohol. rape seed oil, 5 pints ofethyl the fundamental element of. which is' a cellulosic material(cellulose ni-,

for example, and of its solvent, willvary according to'the consistency;

also

vnarily termed a gum.

lthe fluidity of the lacquer and when the sand-paper sults'.

21, 1927. Serial n., 227,a51.

terial of the abrasive fabric. The result of using a solution such asNo. I is not-only to act asa' spreader or filler material with respectto the cellulosic material, but to increase the hardness andadhesiveness of the coating while the result of using Solution No." IIis to act as an emollient, i. e. to produce'or to increase a conditionof flexibility. Neither the resins of Solution I nor the oil of SolutionII, however, are the active agents'which retain the abrasive grains onthe pap'erfthat' function being exera new Your, assxeuoa ro Benn-min mconi cised by the cellulojsic material of the cellulosic solution.

The cellulose mtrateinay be, of any percent nitrogen composition and"other solvents or combinations or proportions, of solvents may beemployed. in place of the specific solvents.

and proportions recited in the formula for the cellulosic solution abovegiven; Awesult which is satisfactory for'many purposes maycelluloiddissolved in a convenientisolvent or mixture of solvents, celluloidnitrate treated with camphor, which is ordi- Such a celluloid solutioncan be used either alone or in admixture with added cinnplior or camphorsubstitutes or gum resins may be added toincreaseor to accentuatehardnessand adhesive qualities,

Camphor or camphor'substitutes act as plasticizers and practicalexperience with the invention indicates best results, both a plasticizerand an oil shouldwbe used. Plasticizers serve to control a lacquer withgood flowing properties is quite desirable for coating urposes. Compacetate may also be emplo ed in place of cellulose nitrate ,with equalThe process of manufacturing sand-paper in accordance with thisinvention cons oating a fabricbacln'ng with the described composition,depositing abrasive grains upon be obtained by using-a composition of Ithat in order to obtain the nds of cellulose y satisfactory res beingcellulose acetate. 7 thiscoatingwhile n a plastic condition and Whenmixed in the proportion of two gald ing by eva oratin -the olvent. Afterlons of the. cellulosicsolution, onegallon of the first ooa :JlhiOcarries the abrasive Solution I and one allon of Solution II, a has drisand-paper is given a I composition willrbe ormed which canbe ap- 'topeoatin of the-samecom 'tion the paper is ,gghbroughly dried, which comtory and does not require any excessive space for dry rooms, handling orother details of operation. The use of the described top coating havingthe composition set forth, presents features of special utility. Such atop coating, so composed, or so constituted, has

the effect of'more or less completely filling i the spaces between theotherwise projecti g partsof the abrasive particles, thereby forming amatrix,-a s it were, through which the abrasive particles as they wearaway,

- gradually penetrate more and morewithout at any time disturbing thematrix effect of said added film.

In most industries in which waterproof sand-paper is advantageouslyused, it is requisite that the rear surface of the fabric backing bealso rendered waterproof. This waterproofing of the paper or fabricfoundation material can be accomplished by the use of any suitablewaterproofing material either before or, after the other side of-thesheet.

is coated with abrasive. It is preferable, however, .to coat the back ofthe fabric with the samecomposition which is used in waterproofing theface of the fabric. The application of a coat oft this character to theack of the fabric results in a continuous film which obstructs access tothe fibres of the fabric base. Thus no direct'contact between theoperator or the o crating instrumentalities and the fabric 0 the base ispermitted,

and consequently there will be no frictional displacement of such fibreswith respect to eachother. The use, therefore, of this particularcomposition when-used to coat the back of the fabric, presents specialadvantages. r k

Sand-paper produced in accordance with this invention is stable and doesnot deteriorate with the passage of time as is likely to occur insand-paper in which the adhesive character of the coating is made todepend upon oxidation products of oil or varnish compositions. I includewithin the scope of this invention s'andpaper whether made with abacking of paper or any other conventional backsive grit, and a matrixfor attaching said'grit to said backing including cellulosic material, aresinous filler, an emollient containing rape seed oil, and aplasticizer.

In testimony whereof I have hereunto set in y hand.

FRANK JOSEPH CRUPI.

ing material of the sand-paper art as well as articles made from thesand-paper of my invention. I further include within the scope of thisinvention sand-paper whether coated on one or both sides of the fabricbase -or whether used in oneor more coats onthat side which bears theabrasive material.

I claim: As a new article of manufacture, a sandpaper including a fabricbacking, an abra-

